Cooling of pluggable devices in device ports using thermal conductive pedestals

The present application is similar to U.S. patent application Ser. No. 18/226,623, entitled ‘Cooling of Pluggable Devices in Device Ports Using Oblique Angles,’ invented by Adi Bonen and Eran Schwartz, filed the same day herewith, the entire contents of which are incorporated by reference for all purposes as if fully set forth herein.

Embodiments of the invention relate to the cooling of pluggable devices inserted into a device port of an article of manufacture.

Computer circuits generate heat upon continued use; unfortunately, excess heat may lead to performance degradation. For this reason, circuits which generate excess heat may be cooled during operation by diverting the generated heat elsewhere. A common way to do so in a computer is by using a fan to blow air over the heat generating circuits of concern during operation. The airflow created by the fan absorbs a certain amount of the heat generated by the computer circuits, which is then whisked away from the interior of the computer to the exterior of the computer by way of a vent.

Some devices cannot support adequate airflow to cool circuitry in this manner for a variety of reasons. For example, consider, which is an illustration of a devicetypical in the prior art which cannot support adequate airflow to use a fan to cool circuitry within its interior. Devicerepresents a piece of computer network equipment, such as a switch of a size capable of being held in a person's hand. The casing of devicedoes not contain a vent and is too small to incorporate the use of a standard fan, and so no airflow is readily exchanged between its interior and exterior. The casing of deviceneed not be designed to be airtight for the lack of a vent to cause airflow to be insufficient to support cooling of heat generating components contained therein. Further, deviceis also intended to be deployed inside a hermetically sealed enclosure that does not support internal air flow and/or venting. Such a hermetically sealed enclosure is used to protect the enclosed components from environmental conditions, such as water, moisture, and other contaminants, when deployed outside.

The pluggable devices, such as exemplary pluggable devicesand, which may be inserted into one of the device portsof deviceshould not be permitted to overheat. A device port comprises a cavity and an electrical interface. A device port is designed to accommodate the manual insertion of a pluggable device into its cavity so that an electrical connection may be established between the host device (i.e., devicein this example) and the pluggable device. The pluggable device may, in turn, provide additional functionality to the host device, such as allowing the host device to communicate with other equipment in a network.

There are a wide variety of devices which may be manually plugged into a device port, one example being a small form-factor pluggable (SFP) transceiver. A SFP transceiver is a compact, hot-pluggable device that may be used to connect the host device to a network. SFP transceivers may be used to receive data as input from the host device and deliver the data to a recipient over networking fiber optic cables connected to the SFP transceiver. The form factor and the electrical interface of pluggable optical transceivers such as a SFP transceiver are typically specified by a multi-source agreement (MSA).

As a fan cannot be relied upon exclusively to cool circuitry during operation, devices in the prior art also rely upon thermal conduction to remove excess heat. To illustrate an example of how this process is performed in the prior art, consider, which is an illustration of a cross-section of a host deviceshown inin accordance with the prior art. The cross-section of deviceshown inis relative to plane, i.e., it is lengthwise cross section of device.

The device portsshown inare enclosed within a metal cage. Metal cageis typically made out of a thin metal layer and functions to hold the device portsin place within device. In addition to serving as an interface for connecting a pluggable device to a host device, a device port also functions the conduct heat away from any pluggable device inserted into the device port, which will be explained in greater detail below.

To operationally connect any pluggable device inserted into a device port, each device portdepicted inis electronically connected to a first printed circuit board (PCB). In the example of, devicecomprises two printed circuit boards which are in electronic communication with one another, e.g.,depicts first printed circuit board (PCB)and second printed circuit board layer, and electronic signals carried by electrical paths on one of these PCBs may be conveyed to electrical paths on the other. Devicemay utilize two PCBs when deployed in a size constrained environment, such as a hermetically sealed enclosure. In the example of, first PCB, which resides in the upper portionof device, is shorter in length than PCB, which resides in the lower portionof device. The use of two separate and distinct printed circuit boards (PCB) of different sizes allows the device portsto be electronically connected to the upper, smaller PCB while, at the same time, having a position that permits technicians to access the device portswith their fingers, which is necessary as technicians manually insert pluggable devices into device portsduring service. Having the device portsreside in the upper portionof deviceallows for some space underneath and in front of the device ports, which provides sufficient finger access to device portsto technicians.

A metal layeris disposed between first PCBand second PCB. Metal layerprovides mechanical support to first PCB, electrical magnetic interference (EMI) shielding between first PCBand second PCB, and assist with heat conductance. Underneath the second PCB layeris outer base layer, which may also be composed of metal. While not shown in, devicemay be deployed in a hermetically sealed environment, and thus, may itself be enclosed by another device, such as a cable network node.

Electrical components in deviceare difficult to cool during operation, particularly those mounted on PCB, such as the pluggable devices inserted into device ports. To illustrate why,is a cross-sectional illustration depicting how heat travels by conduction through devicein accordance with the prior art. As shown in, devicecomprises two printed circuit boards, namely an upper printed circuit boardand a lower printed circuit board. A portion of the heat generated by components inside the pluggable devices held in device portsis transferred to metal cageby thermal conduction. As the metal cagewarms, a portion of the heat transferred from the metal cageto metal layerwithin device. As shown in, the heat conduction from metal layerto heat conveyance layeris typically implemented through a long and narrow path which reduces the efficiency of heat transfer and results in a significant rise in temperature in the devices held in device ports, which diminishes how much heat can be transferred from these devices through heat conveyance layerand the outer base layer.

Approaches for improved cooling in one or more device ports of an article of manufacture are presented herein. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the invention described herein. It will be apparent, however, that the embodiments of the invention described herein may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form or discussed at a high level in order to avoid unnecessarily obscuring teachings of embodiments of the invention.

Embodiments of the invention may be used to cool circuitry during operation using innovations involving heat or thermal conduction. Advantageously, embodiments may be used in operational environments that do not possess or support sufficient airflow to facilitate cooling, such as for example the interior of devices lacking adequate venting, circuitry executing in a hermetically sealed environment, devices deployed in high altitude, and devices deployed in a vacuum or orbital environment.

Embodiments of the invention have particular utility in providing improved cooling to one or more device ports used in a wide range of devices. For simplicity, to represent the wide range of devices which may employ an embodiment of the invention, a device that employs the invention shall be referred to herein as an article of manufacture. Specific examples of the types of devices which may be represented by the term articles of manufacture include but are not limited to the following: a wireless communication device, an Ethernet switch, an Optical Line Terminal (OLT), a Remote PHY device (RPD), and a Remote MACPHY device (RMD).

An article of manufacture of an embodiment comprises one or more device ports. A device port comprises a cavity and an electrical interface. The cavity portion of a device port accommodates the insertion of a pluggable device. The electrical interface portion of a device portion accommodates the establishment of an electrical connection between the pluggable device and the article of manufacture having the device port. For example, a device port may have a cavity that is sized and shaped to accommodate the insertion of, and subsequently coupled to, an optical module, a small form-factor pluggable device (SFP), an XFP optical transceiver, an SFP+ optical transceiver, a Quad Small Form-factor pluggable plus (QSFP+) device, and a CF2 device.

is a cross-sectional illustration of device, an article of manufacture having improved cooling in one or more device ports using thermal conductive pedestals in accordance with one embodiment of the invention. Devicecomprises outer base layerand comprises a plurality of device portsthat are formed using a metal cage. Metal cageis mounted on printed circuit board. Printed circuit boardmay be operationally connected to printed circuit board. Metal layermay be disposed between printed circuit boardand printed circuit board.

Notably, embodiments of the invention employ one or more single-piece thermal conductive pedestals. The upper portion of each of the one or more single-piece thermal conductive pedestalsis in thermal contact with the metal cageportion forming each of the device ports. Each of the one or more single-piece thermal conductive pedestalsis formed from the same physical piece which serves as, at least a portion of, a physical exterior and base of the article of manufacture, forming a short and wide heat path from the pluggable optical transceivers held in device portsand the enclosure on which deviceis mounted. For example, the one or more single-piece thermal conductive pedestalsare formed out of the same physical piece as outer base layer. Thermal conductive pedestalsand outer base layermay be made from metal, such as but not limited to aluminum.

The one or more thermal conductive pedestalsare in thermal contact with each of the device ports; that is to say, each of the device portsmay easily transfer heat using thermal conduction to the one or more thermal conductive pedestals. In one embodiment, metal cagedirectly abuts against both the pluggable devices held in the plurality of device portsand one or more single-piece thermal conductive pedestals. In such an embodiment, heat may be easily transferred from the pluggable devices held in device portsto the metal cage, and thereafter from the metal cageto the one or more single-piece thermal conductive pedestals. In another embodiment, the one or more single-piece thermal conductive pedestalsare in direct physical contact with the plurality of pluggable devices held in device portswithout the presence of the metal cagebeing therebetween. In either embodiment, heat generated by the pluggable devices held in device portsmay be transferred either directly to the one or more single-piece thermal conductive pedestalsor indirectly by way of the metal cage.

In an embodiment, a malleable thermal conductive material is disposed on the portion of one or more single-piece thermal conductive pedestalsmaking physical contact with either metal cageor the device ports. Doing so allows for a solid, uninterrupted physical connection between the two surfaces, thus providing an optimal boundary for heat to be transferred between two surfaces using thermal conduction.

The one or more single-piece thermal conductive pedestalsmay protrude from outer base layerand extend through a variety of structures or layers in the article of manufacture. For example, in an embodiment, the one or more single-piece thermal conductive pedestalsextend through one or more printed circuit boards (PCBs). In another embodiment, the one or more single-piece thermal conductive pedestalsextend through a structural layer which is not a printed circuit board (PCB). These embodiments are not mutually exclusive, as one or more single-piece thermal conductive pedestalsmight extend through one or more printed circuit boards (PCBs) and also through one or more other layers which are not a PCB.

Advantageously, embodiments of the invention allow for the heat generated by certain circuitry and components, such as but not limited to pluggable devices held in device ports, to be transferred by thermal conduction to one or more thermal conductive pedestals. After the heat is transferred to one or more thermal conductive pedestals, the heat will cause outer base layerto increase in temperature, as one or more thermal conductive pedestalsand outer base layerare a single piece. Thereafter, the heated outer base layerwill radiate or conduct heat to the exterior of the article of manufacture; thus, heat may be continuously transferred away from device portsto the exterior of the article of manufacture without practical limit.

Certain embodiments may be designed to provide increased finger access to device ports, which is helpful when a technician manually inserts a pluggable device into a device port. Embodiments may do so using certain structure having oblique angles, and in doing so, allow sufficient finger access to device ports using a single printed circuit board (PCB) rather than employing an upper and lower PCB, which is a substantial savings in cost of materials, eliminates the complexity of conveying electrical signal between PCBs, and reduces the complexity in cooling circuitry, e.g., all components are easier to cool directly into the base of the device. To illustrate such an embodiment, consider, which is a cross-sectional illustration of device, an article of manufacture having improved cooling in one or more device ports using oblique angles in accordance with another embodiment of the invention.

Device, shown in, possesses a mechanical enclosure having a top portionand an outer base layerserving as a bottom portion. Devicepossess device portsthat are formed by metal cage. Notice that metal cageis at an oblique angle relative to printed circuit board; that it is say, that metal cageruns neither parallel nor perpendicular to printed circuit board. As a result, the openingsof device portsinto which pluggable devices are inserted are further away from the surface of printed circuit boardthan the opposing endsof the device portswhere the pluggable devices are electrically connected to printed circuit board. This oblique angle of metal cageprovides finger access to the opening of device ports. As a result, device portsmay be electronically connected to a single printed circuit boardwhile still providing finger access to the device portsto technicians; consequently, the embodiment shown inneed not include two or more printed circuit boards to support use of device portshaving finger access and without requiring enlargement of the area occupied by device.

One or more thermal conductive pedestalsare in thermal contact with each of the device ports; that is to say, each of the pluggable devices held in device portsmay easily transfer heat using thermal conduction to the one or more thermal conductive pedestals. In one embodiment, metal cagedirectly abuts against both the plurality of the pluggable devices held in device portsand one or more single-piece thermal conductive pedestals. In such an embodiment, heat may be easily transferred from the pluggable devices held in device portsto the metal cage, and thereafter from the metal cageto the one or more single-piece thermal conductive pedestals. In another embodiment, the one or more single-piece thermal conductive pedestalsare in direct physical contact with the plurality of the pluggable devices held in device portswithout the presence of the metal cagebeing therebetween. In either embodiment, the surface of the one or more single-piece thermal conductive pedestalsclosest to the device portsis angled the same relative to the device ports. This way, the surface in the one or more single-piece thermal conductive pedestalsis as close as possible to the surface of the device ports, and the heat generated by the pluggable devices held in device portsmay be transferred either directly to the one or more single-piece thermal conductive pedestalsor indirectly by way of the metal cage.

In an embodiment, a malleable thermal conductive material is disposed on the portion of the one or more single-piece thermal conductive pedestalsmaking physical contact with metal cageforming device ports. Doing so allows for a solid, uninterrupted physical connection between the two surfaces, thus providing an optimal boundary for heat to be transferred between two surfaces using thermal conduction.

As shown in, those in the art shall appreciate that the one or more single-piece thermal conductive pedestalsmay extend through PCB. While not shown, those in the art shall appreciate that the one or more single-piece thermal conductive pedestalsmay extend through a structural layer other than PCB.

Advantageously, the approach shown inpermits increased finger access to device ports using a single printed circuit board (PCB) rather than employing an upper and lower PCB, which is a substantial savings in cost of materials, eliminates the complexity of conveying electrical signal between PCBs, and reduces the complexity in cooling circuitry, e.g., all components are easier to cool directly into outer base layer. Further, having the surface of the one or more single-piece thermal conductive pedestalsat an oblique angle relative to the surface of PCBallows the heat absorbing contact of the one or more single-piece thermal conductive pedestalsto be greater in length than if the same surface ran parallel to PCB. The increased length in contact surface of the one or more single-piece thermal conductive pedestalspermits the pedestals to absorb an increased amount of heat, which can be discharged to the external environment via outer base layerof the article of manufacture.

In the foregoing specification, embodiments of the invention have been described with reference to numerous specific details that may vary from implementation to implementation. Thus, the sole and exclusive indicator of what is the invention, and is intended by the applicants to be the invention, is the set of claims that issue from this application, in the specific form in which such claims issue, including any subsequent correction. Any definitions expressly set forth herein for terms contained in such claims shall govern the meaning of such terms as used in the claims. Hence, no limitation, element, property, feature, advantage or attribute that is not expressly recited in a claim should limit the scope of such claim in any way. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.